This invention relates to an objective for lens systems having extremely high speed and a wide angle of view, useful for photographic and other purposes. It is a lens of the same general type as that disclosed in the present applicant's Glatzel U.S. Pat. No. 3,915,558, granted Oct. 28, 1975, the disclosure of which is incorporated herein by reference. The prior patent may be referred to for convenience as the "main patent," and the present invention may be regarded as an improvement on the main patent. By following certain design principles or rules as set forth below, it is found that an improved image can be produced, as compared with the image produced by the lens of the main patent.
Moreover, the present invention provides a lens of somewhat greater power or speed as compared with the lens of the main patent, and having at least in some examples a somewhat wider field of view than the lens of the main patent, without sacrificing the quality of the image.